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Key elements in a surveillance system Patrick Rolland EPIET / EUPHEM Intro Course 2012. &. Le fil rouge in surveillance?. Surveillance is Information for action!. Good reminder: surveillance?. Langmuir AD., 1963

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Key elements in

a surveillance system

Patrick Rolland

EPIET / EUPHEM Intro Course 2012

&


Le fil rougein surveillance?

Surveillance is

Information for action!


Good reminder: surveillance?

  • Langmuir AD., 1963

    “Systematic collection, consolidation, analysis and dissemination of data on specific disease”

  • Thacker SB., 1996

  • “The final link is the application of these data to prevention and control”


Good reminder: surveillance loop

Objectives

Evaluation

Data collection

Data analysis

Action!

Information


Aim and content of the lecture

  • Aim: To understand key elements in a surveillance system

    • From a clear understanding of the purpose

    • To the right dissemination of information

  • Content

    • Main objectives of a surveillance system

    • Checklist of key elements, step by step


Main objectives of

a surveillance system


Main objectives

  • Describe: produce information in terms of TPP

  • Alert: detect epidemics or emerging events

  • Evaluate: assess prevention or control measures

  • And also:

    • Generate hypotheses for research

    • Detect changes in health practice

    • Plan public health actions and resources


But keep in mind the goal!

Surveillance is

Information for action!

By implementation of prevention and control measures

In order to reduce morbidityand mortality


Describe: Time = Graph

Weekly incidence rate of flu-likesyndromes, 2009-2012, France

Source: GP network “Réseau unifié”

Incidence (per 100,000)

Week


Describe: Place = Map

Weekly incidence rate

of acute diarrhea

(per 100,000)

1 to 7 march 2012, France

Source: GP network “Réseau sentinelles”


Describe: Person = Table

Characteristicsof persons

Severe cases of influenza, winter 2011-2012, France

Source: Intensive care units Network

Burden


Exceedence

Alert: detect an epidemic

Weekly incidence of flu-like syndromes, 2007-2012, France

Source: GP network “Réseau sentinelles”

Incidence

Threshold

Incidence (per 100,000)

Week


Emergence of W135

Alert: detect an emerging phenomena

Invasive meningococcal infectionsby serogroup B, C, W135 et Y, 1985-2006, France

Source: InVS, NRC for meningococci

B

Y

C

W135

Number of cases

Year


Vaccination

implementation

Evaluate: prevention/control measure

Cases of Pertussis, England and Wales, 1940-1999

80

40

Number of cases (x 1000)

Vaccinate coverage (%)

0

Year


Reinforced surveillanceNew investigation guideUrine antigen testing

Evaluate: prevention/control measure

Cases of legionellosis, 1988-2011, France

Source: Notifiable disease, InVS

No cases

Incidence

Number of cases

Incidence (per 100,000)

Year


Key elements in a

surveillance system


Key elements

  • Justification of implementation

  • Objectives of the system

  • Types of system

  • Case definition

  • Population under surveillance

  • Data providers and data sources

  • Data elements and data collecting tools

  • Flow chart and data transmission

  • Data validation and data analysis

  • Dissemination and communication data

  • Human and financial resources

  • Data security and confidentiality

  • Evaluation of system


Key elements

  • Justification of implementation

  • Objectives of the system

  • Types of system

  • Case definition

  • Population under surveillance

  • Data providers and data sources

  • Data elements and data collecting tools

  • Flow chart and data transmission

  • Data validation and data analysis

  • Dissemination and communication data

  • Human and financial resources

  • Data security and confidentiality

  • Evaluation of system


Justification of implementation

  • Ask yourself two main questions:

    • Should this event be under surveillance?

      • High frequency?

      • High severity?

      • High socioeconomic cost?

    • Do some prevention or control measures exist?

  • And these two additional questions:

    • Do we have existing data that already answer?

    • Do we have resources to set up a new system?


Health events under surveillance

  • Infectious diseases

    • Notifiable diseases

    • Health-care associated infections (HCAI)

    • Vaccine-preventable diseases

    • Food and waterborne diseases

    • Sexually transmitted infections (STI)

    • Zoonoses

    • Vector-borne diseases

  • But also?


Health events under surveillance

  • Chronic diseases and injuries: cancers, accidents, traumas, cardiovascular diseases, etc.

  • Occupational health: cancers, musculoskeletal disorders, respiratory diseases, mental health, etc.

  • Environmental hazards: air pollution, ionizing radiations, heat/cool waves, water/soil pollution, etc.


Key elements

  • Justification of implementation

  • Objectives of the system

  • Types of system

  • Case definition

  • Population under surveillance

  • Data providers and data sources

  • Data elements and data collecting tools

  • Flow chart and data transmission

  • Data validation and data analysis

  • Dissemination and communication data

  • Human and financial resources

  • Data security and confidentiality

  • Evaluation of system


Objectives of the system

  • Primary objective: To describe a health-related event in population-based or in a specific population

  • With two possible aims (sometimes both):

    • To alertby early detection of epidemics or emerging pathologies that need timely action

    • To evaluatethe efficiency of prevention orcontrol measures


Key elements

  • Justification of implementation

  • Objectives of the system

  • Types of system

  • Case definition

  • Population under surveillance

  • Data providers and data sources

  • Data elements and data collecting tools

  • Flow chart and data transmission

  • Data validation and data analysis

  • Dissemination and communication data

  • Human and financial resources

  • Data security and confidentiality

  • Evaluation of system


Passive and active system

  • Consideration useful for discussion

  • Passive: “The data come to you”

    • Data collection based on existing information

    • Simple, not burdensome but could be incomplete

    • E.g.: notifiable diseases, deaths, emergency data

  • Active: “You go towards the data”

    • Data collection specially set up

    • Good quality of data but required resources

    • E.g. : injuries, non-notifiable infectious diseases, etc.


E.g. of passive system

% of gastroenteritis among emergency consultations, seasons 2010-2011 and 2011-2012, Aquitaine, France

Proportion of cases

Week


E.g. of active system

Cases of envenomation by Physalia Physalis reported bylifeguards, Aquitaine Atlantic Coast, Summer 2011, France

Number of cases

Day


Exhaustive vs. sentinel system

  • Important consideration for data analysis

  • Severe diseases or low-frequency diseases requiring timely action

    • Exhaustive system (= all providers)

    • E.g.: cancers registries, notifiable diseases

  • High-frequency diseases or less-severe diseases

    • Sentinel system (= selected providers)

    • E.g.: seasonal flu, occupational diseases (except cancers)


3. Skin cancer

2. Colorectal cancer

1. Breast cancer

E.g. of exhaustive system

Cancers among women, Year 2005, Gironde, France

Source: Cancerregistry of Gironde

Cancer causes

Number of cases


E.g. of sentinel system

Prevalence of occupational diseases (except cancers),Year 2010, Region of Aquitaine, France

Source: Sentinel Network of occupational physicians (n=92)


Case vs. syndromic system

  • Case system (traditional system)

    • Targets a defined health-related event

    • E.g.: mesothelioma, Lyme disease, diabetes, etc..

  • Syndromic system (“before diagnosis”)

    • For early detection, evaluation of event impact

    • Based on existing activity data, real-time collection, analysis and interpretation data

    • E.g.: emergency services, virology labs, deaths certificates, medicine sales, absence in schools, etc.


E.g. of case system

Occupations at risk for mesothelioma, France

Source: Program of Mesothelioma Surveillance (1998-2012), InVS

Occupations

Odds-ratio (95% CI)


E.g. of syndromic system

% of gastroenteritis among emergency consultations, seasons 2010-2011 and 2011-2012, Aquitaine, France

Proportion of cases

Week


Key elements

  • Justification of implementation

  • Objectives of the system

  • Types of system

  • Case definition

  • Population under surveillance

  • Data providers and data sources

  • Data elements and data collecting tools

  • Flow chart and data transmission

  • Data validation and data analysis

  • Dissemination and communication data

  • Human and financial resources

  • Data security and confidentiality

  • Evaluation of system


Case definition

  • The “heart” of the system!

  • Must be clear and simple

  • Based on criteria:clinical, biological, epidemiological

  • May include:

    • Classification (possible, probable, confirmed)

    • TPP (Time-Place-Person) information


Clinical criteria

E.g. for measles definition as notifiable disease

Laboratory criteria

Source:

Case definitions of notifiable diseases

Commission Decision 2008/426/EC – 28-IV-2008

Epidemiological criteria

Case classification


Key elements

  • Justification of implementation

  • Objectives of the system

  • Types of system

  • Case definition

  • Population under surveillance

  • Data providers and data sources

  • Data elements and data collecting tools

  • Flow chart of data and data transmission

  • Data validation and data analysis

  • Dissemination and communication data

  • Human and financial resources

  • Data security and confidentiality

  • Evaluation of system


Population under surveillance

  • Depends on characteristics of health-event

  • E.g.: Hemolytic Uremic Syndrome (HUS)

    • Rare disease that predominantly affects children, needs timely action in outbreak

    • Population under surveillance (France): children (< 15 years) hosted in pediatric and nephrology hospital services (N=31)


Key elements

  • Justification of implementation

  • Objectives of the system

  • Types of system

  • Case definition

  • Population under surveillance

  • Data providers and data sources

  • Data elements and data collecting tools

  • Flow chart and data transmission

  • Data validation and data analysis

  • Dissemination and communication data

  • Human and financial resources

  • Data security and confidentiality

  • Evaluation of system


Data providers and data sources

  • Data providers: health professionals, laboratories, health insurance funds, civil status offices, etc.

  • Data sources

    • Administrative: death certificates, hospital systems, etc.

    • Medical: patients folders, notifiable diseases, etc.

    • Biological: virology, bacteriology, toxicology samples

    • Environmental: air pollution sensors, individual ionizing radiations card for exposed workers, etc.


One NRC perinfectious disease

E.g. data provider: NRC (France)

47 National Reference Centers and 34 Associated Laboratories

Anaérobies et Botulisme (LA)

Arbovirus (LA)

ATNC

Brucella

Borrelia (LA)

Campylobacter & Helicobacter

Charbon (LA)

Chlamydiae

Cytomégalovirus

Enterovirus

Escherichiacoli & Shigella (LA)

Francisellatularensis

Gonocoques

Haemophilusinfluenzae

Legionella

Leishmania

Mycobactéries et résistance des mycobactéries

Paludisme (2 co-responsables)

Pneumocoques

Résistance aux antibiotiques (LA)

Rickettsia, Coxellia & Bartonella Virus de la rougeole

Staphylocoques VIH

StreptocoquesVirus Influenza

Syphilis Virus entériques

Trichinella Virus des hépatites A et E

Toxoplasmose Virus des hépatites B, C et Delta

Arbovirus

Arbovirus & influenza virus en AG

Charbon

Borrelia

Anaérobies et Botulisme

Chimiorésistance du paludisme

en Antilles Guyane

Coqueluche et autres bordetelloses

Corynebactéries toxinogènes

Escherichiacoli & Shigella

Fièvres hémorragiques virales

Leptospires

Listeria

Méningocoques

Mycologie et antifongiques

Peste et autres yersinioses

Rage

Salmonella

Résistance aux antibiotiques

Streptocoques (LA)

Virus des Hépatites B & C (LA)

Vibrions et cholera

Virus Influenza

15 NRC

and 3 AL

Pasteur Institute

(Paris)

32 NRC and 31 AL

Within hospitals,

universities, other

research institutes


E.g. data source: ND (France)

27 notifiable diseases (ND) require surveillance and timely action

Frequent ND (n=14)

Infrequent ND (n=10)

  • Botulisme

  • Brucellose

  • Chikungunya

  • Dengue

  • Fièvres typhoïdes et paratyphoïdes

  • Hépatite aiguë A

  • Infections invasives à méningocoques

  • Légionellose

  • Listériose

  • Rougeole

  • Saturnisme de l’enfant mineur

  • MCJ et ESST

  • Toxi-infection alimentaire collective

  • Tuberculose

  • Choléra (RSI)

  • Diphtérie

  • Fièvres hémorragiques africaines

  • Fièvre jaune (RSI)

  • Paludisme autochtone et paludisme importés dans DOM

  • Peste (RSI)

  • Poliomyélite

  • Rage

  • Typhus exanthématique

Bioterrorism-related ND (n=3)

  • Charbon, Tularémie, Variole

4 ND require surveillance only

  • Infection à VIH quel qu’en soit le stade

  • Hépatite aiguë B

  • Tétanos

  • Mésothéliome

  • (entrée en 2012)


Key elements

  • Justification of implementation

  • Objectives of the system

  • Types of system

  • Case definition

  • Population under surveillance

  • Data providers and data sources

  • Data elements and data collecting tools

  • Flow chart of data and data transmission

  • Data validation and data analysis

  • Dissemination and communication data

  • Human and financial resources

  • Data security and confidentiality

  • Evaluation of system


Nominative data on patient and provider

E.g. French form

for mesothelioma

notiable disease

Anonymous data on patient diagnosis (by clinician&pathologist)

Dates and signatures of provider and sanitary authority


Key elements

  • Justification of implementation

  • Objectives of the system

  • Types of system

  • Case definition

  • Population under surveillance

  • Data providers and data sources

  • Data elements and data collecting tools

  • Flow chart and data transmission

  • Data validation and data analysis

  • Dissemination and communication data

  • Human and financial resources

  • Data security and confidentiality

  • Evaluation of system


E.g. of flow chart: ND (France)

Politic of Health

Public Health High Council

HealthRegional Agencies

Declaration

Patient

Ministry of Health

Alert

Health professionals, laboratories, etc.

ReferenceCenters

Alert

Partners

National/International

Experts Networks

Clinicians/Pathologists


Data transmission

  • Reliable and fast

    • Electronic: e-mails, websites

    • And: phone, fax and mail

  • Low frequency

    • Daily

    • Weekly

    • Monthly

  • Secure

    • Regularity, punctuality, exhaustiveness

    • And don’t forget the “Zero reporting”


Key elements

  • Justification of implementation

  • Objectives of the system

  • Types of system

  • Case definition

  • Population under surveillance

  • Data providers and data sources

  • Data elements and data collecting tools

  • Flow chart and data transmission

  • Data validation and data analysis

  • Dissemination and communication data

  • Human and financial resources

  • Data security and confidentiality

  • Evaluation of system


Data validation and data analysis

  • Data validation

    • Missing data

    • Duplicates

    • Data quality

  • Data analysis

    • Indicators: frequency, severity

    • Methods: descriptive, analytical

    • Illustrations: tables, graphs and maps

    • Keep in mind: Time-Place-Person!


Temperature

2003

1999-2002

2003

Deaths

1999-2002

E.g. of data analysis: time series

Daily deaths, summers 1999-2002 vs. 2003, France

Source: Syndromic Program, InVS

Number of deaths

Temperature (°C)

Day (25 June to 19 august)


Key elements

  • Justification of implementation

  • Objectives of the system

  • Types of system

  • Case definition

  • Population under surveillance

  • Data providers and data sources

  • Data elements and data collecting tools

  • Flow chart and data transmission

  • Data validation and data analysis

  • Dissemination and communication data

  • Human and financial resources

  • Data security and confidentiality

  • Evaluation of system


Dissemination/communication data

  • Systematic and regular

    • For stakeholders, decisions makers

    • For other professionals, public, medias

  • Adapted

    • To “Those who need to know”

    • To the urgency of the situation

  • Format

    • Report, article, flash news, press releaseetc.

    • But also: phone, e-mail, fax, mail

  • Factor of motivation/improvement


E.g. report at local level

“Point épidémio”

France, Bordeaux

(InVS, south west)

Weekly report on health status of population

Topics:

Outbreaks

Seasonal pathologies

Notifiable diseases

Virology surveillance

Deaths


E.g. report at international level

CDC (USA)

WHO (Switzerland)


E.g. press release

At local level(e.g. France, Bordeaux)

At international level (e.g. Europe)


Key elements

  • Justification of implementation

  • Objectives of the system

  • Types of system

  • Case definition

  • Population under surveillance

  • Data providers and data sources

  • Data elements and data collecting tools

  • Flow chart and data transmission

  • Data validation and data analysis

  • Dissemination and communication data

  • Human and financial resources

  • Data security and confidentiality

  • Evaluation of system


Human and financial resources

  • From the budget to the expenses

    • Salaries, travels, equipments, furniture, etc.

    • Useful to negotiate resources, check the workplan, assess the cost of the system


Key elements

  • Justification of implementation

  • Objectives of the system

  • Types of system

  • Case definition

  • Population under surveillance

  • Data providers and data sources

  • Data elements and data collecting tools

  • Flow chart and data transmission

  • Data validation and data analysis

  • Dissemination and communication data

  • Human and financial resources

  • Data security and confidentiality

  • Evaluation of system


Data security and confidentiality

  • “Critical point” in surveillance system

  • Public heath data

    • Often personal and private in nature

    • Might directly identified individuals

  • Take into account policiesand protection forpersonal data

    • Data collectionoften under laws


Key elements

  • Justification of implementation

  • Objectives of the system

  • Types of system

  • Case definition

  • Population under surveillance

  • Data providers and data sources

  • Data elements and data collecting tools

  • Flow chart and data transmission

  • Data validation and data analysis

  • Dissemination and communication data

  • Human and financial resources

  • Data security and confidentiality

  • Evaluation of system


Aims of evaluation

  • Ask yourself the fundamental question:

    • Have the objectives been met?

  • And these additional questions:

    • Did the system generate needed answers?

    • Was the information timely?

    • Was it useful for decisions makers?

    • How was the information used?

    • What could be done to improve the “attributes”?

    • Is it useful to continue the surveillance?


The “9” attributes of a system (1)

  • Simplicity: refers to structure and ease operation

  • Flexibility: ability to adapt to changing needs

  • Data quality: refers to data completeness&validity

  • Acceptability: willingness of persons and organizations to participate

  • Sensitivity: refers to proportion of detectedcases by the system (“A / A + C”)


The “9” attributes of a system (2)

  • PVP:refers to proportion of reported the cases that actually have the event (“A / A + B”)

  • Representativeness:ability to describe the event over time and its distribution in the population

  • Timeliness:reflects the speed between system steps of the system

  • Stability: refers to reliability and availability



Main messages

  • Justification

    • Relevance of the event to be under surveillance

    • Existence of prevention and control measures

  • Objectives and aims

    • To describe – To alert – To evaluate

    • To produce information for action

    • In order to reduce morbidity and mortality

  • Requirements

    • “Good data”, involvement of stakeholders

    • Regular evaluation of the system


One useful book

3rd edition

September 2010

Lisa M. Lee

et al.


Don’t forget the surveillance loop!

Objectives

Evaluation

Data collection

Data analysis

Action!

Information


Le fil rougein surveillance?

Surveillance is

Information for action!


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